North Korea leader Kim Jong-un said his country no longer needs to conduct nuclear or intercontinental ballistic missile tests because it has completed weaponising nuclear arms.

"To guarantee suspension of nuclear tests in a transparent manner, the republic's northern nuclear test site will be abolished," the KCNA said after Mr Kim convened this year's first plenary session of the Central Committee of the ruling Worker’s Party on Friday.

"The overall projects of the party and the country will be geared towards building of a socialist economy, and all our efforts will be made towards it."

US President Donald Trump welcomed the statement.

"North Korea has agreed to suspend all Nuclear Tests and close up a major test site," he wrote on Twitter. "This is very good news for North Korea and the World - big progress! Look forward to our Summit."

North Korea has previously defended its nuclear and missile programs in the face of worldwide condemnation and sanctions as a necessary deterrent against perceived US hostility.

Tensions eased significantly after Mr Kim called in a New Year's speech for lower military tensions and improved ties with South Korea.